纳米二氧化钛粒子的制备研究

Preparation of nano-TiO2 particles

以钛酸四丁酯为原料通过溶胶凝胶法合成二氧化钛纳米粒子,通过实验发现:滴加时间对粒径有一定的影响,反应液的滴加时间应控制在2~3 h;反应温度对粒径和溶胶稳定性和分散性都有着较大的影响,应控制在25~35℃;反应中的抑制剂硝酸、冰醋酸和乙酰丙酮配合使用时有明显的效果,过程中将添加剂置于原料液中是核心步骤,否则生成物会迅速团聚形成凝胶;反应过程二氧化钛的转化率和温度和添加剂的影响不大,但较低的温度会影响中间产物水解而影响转化率,控制温度在30~40℃为佳,结合粒径变化可控制在30~35℃;氢离子浓度对粒径有一定影响,浓度较低时,由于带电胶团的吸附作用粒径会一定程度下降,但不断增大时,会因为挤压Stern层而降低分子间斥力而增大粒径。

Herein,various factors were investigated for the preparation of narrowly dispersed spherical particles of titanium dioxide by sol-gel method.It was found that the dropping time in the self-dispensing reaction solution and the dropping solution should be controlled at 2~3 h;the reaction temperature was on the particle size and the sol.Stability and dispersibility have a greater impact,should be controlled at 25~35 ℃;the reaction of the additive nitric acid,glacial acetic acid and acetylacetone have a significant effect when combined,and the additive should be placed in the reaction solution,otherwise it will lead to reaction failure;the conversion rate of titanium dioxide in the reaction process has little effect on the temperature and the additive,but the lower temperature will affect the reaction,the better temperature is 30~40 ℃,combined with the results above,the temperature can be controlled at 30~35 ℃.The concentration of hydrogen ions has a certain effect on particle size,when the concentration at a low lever,the particle size will decrease to a certain extent due to the adsorption of charged micelles,if keep increasing its concentration,as the Stern layer is squeezed,so the intermolecular repulsive force is reduced resulting the increasing of particle size.Reasonable explanations were provided.